Whole-House Dehumidification Using Dew Point and Duct Control
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Solution Overview
Problem
Conventional whole-house dehumidifier systems face issues such as re-evaporation of moisture from air conditioning coils, dependency on air filter cleanliness, and variable performance due to differences in ductwork impedance, leading to inconsistent dehumidification results.
Innovation Solution
The system measures dew point and relative humidity to control the operation of the dehumidifier and HVAC blowers, allowing for controllable connection and disconnection from ductwork, and cycling the HVAC blower for better air circulation, using sensors to determine the need for dehumidification and adjust the dehumidifier's operation based on user-set dew point targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the dehumidifier is connected to the HVAC system ductwork to achieve whole-house dehumidification, then the dehumidification coverage is improved, but the performance becomes variable due to differences in ductwork impedance
Solution Approach 1:
The system segments the ductwork into different impedance zones and provides independent control for each zone through separate blowers and dampers, allowing optimization of dehumidification performance in each segment rather than treating the entire ductwork as a single unit
Solution Approach 2:
The system dynamically adjusts blower speeds and damper positions based on real-time sensor feedback from each zone, enabling adaptive control that compensates for varying ductwork impedance and maintains consistent performance across different building configurations
2Device complexity
If the dehumidifier uses the HVAC system blower to drive air through the ductwork, then the device complexity is reduced, but the dehumidification performance becomes dependent on air filter cleanliness
Solution Approach 1:
The system separates the air handling function into dedicated zone blowers for each duct segment, isolating the dehumidification process from the HVAC air filter, so that filter cleanliness no longer affects dehumidification performance
Solution Approach 2:
The system introduces dedicated zone blowers as intermediary devices between the dehumidifier and the ductwork, providing a controlled air pathway that is independent of the HVAC system's air filter and blower
3Device complexity
If the dehumidifier returns air to a point downstream from the air conditioning unit, then the system complexity is reduced, but moisture re-evaporation from the air conditioning coils occurs
Solution Approach 1:
The system takes preliminary action by cooling the air conditioning coils and removing their moisture content before the dehumidified air is returned to the system, preventing re-evaporation from occurring
Solution Approach 2:
The system dynamically controls the timing and temperature of air return based on the thermal state of the air conditioning coils, adjusting the air path to avoid contact with warm, moist coils that would cause re-evaporation
4Ease of operation
If conventional systems use relative humidity measurements to control dehumidification, then the control simplicity is maintained, but the dehumidification precision is insufficient due to temperature-dependent variability
Solution Approach 1:
The system changes the control parameter from relative humidity to dew point temperature, which is temperature-independent and provides a more accurate and consistent measure of moisture content for control purposes
Solution Approach 2:
The system replaces the simple relative humidity sensor-based control with a more sophisticated dew point measurement system that uses temperature and humidity sensors to calculate dew point, providing superior control precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures consistent and efficient dehumidification by addressing the re-evaporation issue, reducing dependency on air filter cleanliness, and optimizing performance across different ductwork configurations, resulting in improved humidity control within buildings.
Implementation Method 1
The system measures dew point and relative humidity to control the operation of the dehumidifier and HVAC blowers
Implementation Method 2
This invention is directed to systems and methods for dehumidifying a space within an interior of a building
Implementation Method 3
cycling the HVAC blower for better air circulation
Data Source
AI summary
A dehumidifier system is connected to an interior space of a building through supply and return ducts, either directly and/or through an HVAC system. Controllable dampers can be used to select how the dehumidifier system is connected to the interior space and the HVAC system. The dehumidifier determines the dew point of the ambient air from temperature and relative humidity measurements taken at location(s) of relative humidity and temperature sensors. Based on the determined dew point, the dehumidifier system determines whether to operate. The temperature and relative humidity sensors can be located in the interior space or within the dehumidifier, where they project into the air stream flowing through the dehumidifier. The dehumidifier system operates in response in part to blower calls to the HVAC system and controls the HVAC system and a ventilation system to distribute the dehumidified air and outside air throughout the building.